The attacker fatally shot two women before killing himself in the parking lot after the US leader urged more gun control.
The attack took place on Thursday outside the Cornerstone Church, east of the city of Ames, while a programme was in progress inside.
Authorities had not immediately identified a motive for the attack, and the relationship of the attacker with the victims was not immediately known.
Nicholas Lennie, chief deputy of the Story County Sheriff’s Office, said the attack appeared to be “an isolated, single-shooter incident”.
It came shortly after Biden appealed to Congress to pass legislation to ban assault weapons, expand background checks and implement other gun control measures to address a recent string of high-profile mass shootings.
Those included in May a gun mass shooting at a primary school in Uvalde, Texas in which 19 children were killed along with two teachers and a racist attack at a grocery store in Buffalo, New York in which a gunman killed 10 people.
The violence has renewed a push for federal legislation to address gun violence, but while there has been some progress in bipartisan discussions on some reforms, the effort remains an uphill battle.
“It’s time to act,” Biden said during the emotional speech from the White House. “For the children we have lost, for the children we can save, for the nation we love, let’s meet the moment. It’s time to act.”
A day before Biden spoke, a disgruntled patient fatally shot four people at an Oklahoma hospital before killing himself.
There have been at least 233 mass shootings in the US so far in 2022, according to the gun violence archive.